The overthrow of the Medici regime in Florence in 1494 marks a turning point in the history of Florentine republicanism. Although a vital presence since the thirteenth century, only at the end of 1494 did republicanism inspire the reform of the city government to an extent that led eventually to the establishment of the Consiglio Maggiore.

One clear aim of the constitutional reforms carried out by the Medici regime from 1434 onwards was to have the Councils of the Popolo and of the Commune deprived of their traditional powers. These were then bestowed upon the new Councils of the Cento and of the Settanta, thus making all the more apparent that the Medici's policy did depart significantly from Florentine constitutional tradition. This specific aspect of sixteenth-century Medicean constitutional reform has a great deal to do with the events of late 1494, and in particular with the establishment of the Consiglio Maggiore. This institution was, in fact, regarded as a reinstatement of the old city's councils.

The inability of Piero de' Medici to orchestrate an effective defence policy against Charles VIII, who had crossed the Alps at the end of August 1494, and his haste to surrender Pisa and Sarzana to the French king, led to his exile on 9 November 1494.